wallet: provide WalletBatch to 'RemoveTxs'

Preparing it to be used within a broader db txn procedure.

src/wallet/wallet.cpp

@@ -2388,8 +2388,21 @@ DBErrors CWallet::LoadWallet()
 util::Result<void> CWallet::RemoveTxs(std::vector<uint256>& txs_to_remove)
 {
     AssertLockHeld(cs_wallet);
-    WalletBatch batch(GetDatabase());
+    bilingual_str str_err;  // future: make RunWithinTxn return a util::Result
-    if (!batch.TxnBegin()) return util::Error{_("Error starting db txn for wallet transactions removal")};
+    bool was_txn_committed = RunWithinTxn(GetDatabase(), /*process_desc=*/"remove transactions", [&](WalletBatch& batch) EXCLUSIVE_LOCKS_REQUIRED(cs_wallet) {
+        util::Result<void> result{RemoveTxs(batch, txs_to_remove)};
+        if (!result) str_err = util::ErrorString(result);
+        return result.has_value();
+    });
+    if (!str_err.empty()) return util::Error{str_err};
+    if (!was_txn_committed) return util::Error{_("Error starting/committing db txn for wallet transactions removal process")};
+    return {}; // all good
+}
+
+util::Result<void> CWallet::RemoveTxs(WalletBatch& batch, std::vector<uint256>& txs_to_remove)
+{
+    AssertLockHeld(cs_wallet);
+    if (!batch.HasActiveTxn()) return util::Error{strprintf(_("The transactions removal process can only be executed within a db txn"))};
 
     // Check for transaction existence and remove entries from disk
     using TxIterator = std::unordered_map<uint256, CWalletTx, SaltedTxidHasher>::const_iterator;
@@ -2398,25 +2411,16 @@ util::Result<void> CWallet::RemoveTxs(std::vector<uint256>& txs_to_remove)
     for (const uint256& hash : txs_to_remove) {
         auto it_wtx = mapWallet.find(hash);
         if (it_wtx == mapWallet.end()) {
-            str_err = strprintf(_("Transaction %s does not belong to this wallet"), hash.GetHex());
+            return util::Error{strprintf(_("Transaction %s does not belong to this wallet"), hash.GetHex())};
-            break;
         }
         if (!batch.EraseTx(hash)) {
-            str_err = strprintf(_("Failure removing transaction: %s"), hash.GetHex());
+            return util::Error{strprintf(_("Failure removing transaction: %s"), hash.GetHex())};
-            break;
         }
         erased_txs.emplace_back(it_wtx);
     }
 
-    // Roll back removals in case of an error
+    // Register callback to update the memory state only when the db txn is actually dumped to disk
-    if (!str_err.empty()) {
+    batch.RegisterTxnListener({.on_commit=[&, erased_txs]() EXCLUSIVE_LOCKS_REQUIRED(cs_wallet) {
-        batch.TxnAbort();
-        return util::Error{str_err};
-    }
-
-    // Dump changes to disk
-    if (!batch.TxnCommit()) return util::Error{_("Error committing db txn for wallet transactions removal")};
-
         // Update the in-memory state and notify upper layers about the removals
         for (const auto& it : erased_txs) {
             const uint256 hash{it->first};
@@ -2428,8 +2432,9 @@ util::Result<void> CWallet::RemoveTxs(std::vector<uint256>& txs_to_remove)
         }
 
         MarkDirty();
+    }, .on_abort={}});
 
-    return {}; // all good
+    return {};
 }
 
 bool CWallet::SetAddressBookWithDB(WalletBatch& batch, const CTxDestination& address, const std::string& strName, const std::optional<AddressPurpose>& new_purpose)

src/wallet/wallet.h

@@ -794,6 +794,7 @@ public:
 
     /** Erases the provided transactions from the wallet. */
     util::Result<void> RemoveTxs(std::vector<uint256>& txs_to_remove) EXCLUSIVE_LOCKS_REQUIRED(cs_wallet);
+    util::Result<void> RemoveTxs(WalletBatch& batch, std::vector<uint256>& txs_to_remove) EXCLUSIVE_LOCKS_REQUIRED(cs_wallet);
 
     bool SetAddressBook(const CTxDestination& address, const std::string& strName, const std::optional<AddressPurpose>& purpose);